M 
		
				
				
			
		diskutil list
	diskutil info disk2
	   Read-Only Volume:         Yes
	ouiBonjour Pierro
Est-ce que tu ouvres une session d'utilisateur normale (avec Finder et Dock) dans le volume où est installé High Sierra ?
diskutil list
	Last login: Wed May 20 14:56:39 on ttys000
MacBook-Pro-de-Duteil:~ duteilpierro$ diskutil list
/dev/disk0 (external, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *2.0 TB     disk0
   1:                        EFI EFI                     209.7 MB   disk0s1
   2:                  Apple_HFS Disque secours          2.0 TB     disk0s2
   3:                 Apple_Boot Recovery HD             650.0 MB   disk0s3
/dev/disk1 (external, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *500.1 GB   disk1
   1:                        EFI EFI                     209.7 MB   disk1s1
   2:          Apple_CoreStorage Macintosh HD            499.2 GB   disk1s2
   3:                 Apple_Boot Recovery HD             650.0 MB   disk1s3
/dev/disk2 (external, virtual):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                  Apple_HFS Macintosh HD           +498.9 GB   disk2
                                 Logical Volume on disk1s2
                                 AFCC7381-2820-4A2B-89E0-1FFF68F99288
                                 Unlocked Encrypted
MacBook-Pro-de-Duteil:~ duteilpierro$
	diskutil info disk2
	Last login: Wed May 20 14:57:39 on ttys000
MacBook-Pro-de-Duteil:~ duteilpierro$ diskutil info disk2
   Device Identifier:        disk2
   Device Node:              /dev/disk2
   Whole:                    Yes
   Part of Whole:            disk2
   Device / Media Name:      HTS547550A9E384
   Volume Name:              Macintosh HD
   Mounted:                  Yes
   Mount Point:              /Volumes/Macintosh HD
   Content (IOContent):      Apple_HFS
   File System Personality:  HFS+
   Type (Bundle):            hfs
   Name (User Visible):      Mac OS Extended
   Owners:                   Disabled
   OS Can Be Installed:      No
   Booter Disk:              disk1s3
   Recovery Disk:            disk1s3
   Media Type:               Generic
   Protocol:                 USB
   SMART Status:             Not Supported
   Volume UUID:              ED8FC3F9-39B4-3D7E-8D4B-5F1B8B48013E
   Disk / Partition UUID:    AFCC7381-2820-4A2B-89E0-1FFF68F99288
   Disk Size:                498.9 GB (498876809216 Bytes) (exactly 974368768 512-Byte-Units)
   Device Block Size:        512 Bytes
   Volume Total Space:       498.9 GB (498876809216 Bytes) (exactly 974368768 512-Byte-Units)
   Volume Used Space:        269.3 GB (269283749888 Bytes) (exactly 525944824 512-Byte-Units) (54.0%)
   Volume Free Space:        229.6 GB (229593059328 Bytes) (exactly 448423944 512-Byte-Units) (46.0%)
   Allocation Block Size:    4096 Bytes
   Read-Only Media:          No
   Read-Only Volume:         Yes
   Device Location:          External
   Removable Media:          Fixed
   Virtual:                  Yes
   This disk is a Core Storage Logical Volume (LV).  Core Storage Information:
   LV UUID:                  AFCC7381-2820-4A2B-89E0-1FFF68F99288
   LVF UUID:                 346EED65-C0D4-4459-989E-889FEB907B11
   LVG UUID:                 F3FACF2C-DAA5-4453-8DD6-249FCBB02DCB
   PV UUID (disk):           BC1C6BBC-98AC-4EAB-BB62-9F78C79888B2 (disk1s2)
   Fusion Drive:             No
   Encrypted:                Yes
MacBook-Pro-de-Duteil:~ duteilpierro$
	   Read-Only Volume:         Yes
	defaults read /Vol*/Mac*/System/Lib*/CoreServices/SystemVersion.plist ProductVersion